Telephone



(No Model.)

T. A. WATSON.

. Telephone.

No. 242,722. Patented .Iu| 1e 7,1]881.

UNITED STATES 1 PATENT OFFICE.

THOMAS A. WATSON, OF EVERETT, MASSACHUSETTS.

TELEPHONE.

SPECIFICATION forming part Of Letters Patent NO. 242,722, dated June 7,1881.

Application filed July 1, 1880. I (No model.)

- To all whom it may concern:

The invention is shown embodied in a magr neto-telephone; and it consists, partly, in a novel vibrator or means of converting the sound-waves into electric impulses, and partly in a novel form of magnet and arrangement of pole-pieces therein.

It has been discovered that fibrous material receives and again gives out sound, copying perfectly theintricate vibrations of articulated speech, cotton having been used with success in the ears of deaf persons to perform the time tion of a diseased or imperfect tympannm or ear-drum. I have adapted this principle to telephones by providing a magneto-telephone with a vibrator or sound transmitter or converter consisting of a mass of fibrous magnetic material-such as, for example, a bunch of fine wire looselycolleeted in front of poles of the magnet--such a vibrator being used either with or without a diaphragm of ordinary form.

It is desirable in a magneto-telephone to bring the poles of the magnet as near to the center of the diaphragm or vibrator as possible, to centralize or concentrate the field of force, and to this end I have constructed a horseshoe-magnet having its poles or extremities brought in close proximity to one another, and at the same time I have counterbored the said poles to receive the usual pole-pieces and induction-coils thereon, such arrangement and construction concentrating the magnetic force at the center of the diaphragm in a much greater degree than has hitherto been attained with a horseshoe-magnet.

It is obvious that a vibrator such as described, consisting of a loosely aggregated mass of fibrous material, either magnetic or not, may he used advantageously in connection with the battery-transmitter of usual construction.

Figure 1 is a rear view of a magneto-telephone embodying my invention, showing the magnet properly shaped to centralize the field of force; Fig; 2, a longitudinal section thereof, showing the vibrator employed in connection with the usual diaphragm; Fig.3, a modification in which the fibrous vibrator is used to transform the sound-waves directly into electrical impulses.

The horseshoe-magnet a, instead of being of the usual U shape, having its two sides parallel, is bow-shaped, the extremities or poles I) thereof being bent intoclose proximity to one another, being shown as near together as practicable without actual contact. The said extremities b are parallel and counterbored, as shown at c, to receive the pole-pieces d and induction-coils e, of usual construction. The said'induetion-coils bythis arrangement are completely surrounded by and inclosed in the poles of the magnet, which thus have an exceedingly strong influence on the said coils. When a diaphragm, f, of com mon construction, is used, either with or without a flexible vibrator, this arrangement of the poles brings the magnetic field of force as near as possible to the center of the said diaphragm, which is the part having the greatest vibration.

The vibrator or sound transmitter g, as shown, is a mass or bunch of fine iron wires loosely aggregated to form a light fibrous mass having a considerable interstitial space. This vibrator g is placed in the sound-passage or mouth-piece h, either resting on the diaphragm f, as in Fig. 2, or directly upon the poles surrounding the ends of the pole-pieces d, as in Fig. 3. When needed, a restraining-screen, i, of gauze or netting may be used to retain the vibrator g in place;

No attempt is herein made to give a theoretical explanation of the principle upon which a mass of fibrous material operates as a perfect transmitter or reproducer of sound. It may be owing to the air contained in the interstices of the said fibrous material acting as an elastic cushion of extreme delicacy, or it may be owing to other causes; but the important fact remains that such avibrator or soundtransmitter afi'ords extremely perfect articulation with a sufficient intensity or loudness of sound. Such avibrator may, bya slight modification, be employed in connection With the electrodes of a microphone or battery transmitter of ordinary construction, either with or without the intervention of a diaphragm. For example, electrodes could be substituted for the magnets shown in Figs. 2 and 3. The diaphragm f, with the fibrous vibrator resting thereon, as shown in Fig. 2, would then be combined in the usual way with the electrodes; or,if thediaphragm is to be dispensed with, the vibrator, instead of resting directly upon the magnet, as shown in Fig. 3, would be made to act directly upon the vibratory-electrode placed at or near the center of the same. In either case the fibrous material is held in place, when necessary, by netting or a perforated plate,

- and should always have its interstices in communication with the surrounding atmosphere,

so as to take up directly the vibrations therein, it being obvious that vibrations communicated to the fibrous material through an ordinary solid diaphragm would be materially modified by the passage through the latter.

In the case of a receiving or magneto telephone using a mass of fibrous magnetic or other material as the vibrator, the best results of reproduction, as well as of transmission, are obtained by having the interstices of the vibrator in communication with the external air, as shown in the drawings. In converting electric undulations into sound-vibrations a peculiar operation (not, so far as I am aware, before known) is, however, involved-to wit, that a fibrous vibrator will give to the vibrations imparted to it by said undulations through a receiving diaphragm or magnet a character more closely approximating those of articulate speech.

In using fibrous magnetic material in the vibrator, both in transmitting and receiving, there are distinctive inductive effects that take place independent of the communication of the interstices with the external air. Thisportion of the invention thereforeincludes, broadly, the fibrous vibrator in a receiving-telephone and the fibrous magnetic vibrator in a magneto-telephone, butis limitedin a batterytransmitter to a fibrous vibrator having its interstices in communication with the atmosphere, and receiving its vibrations therefrom.

I claim-- 1. A telephonic receiver com prisin g,' in combination with the other elements of said instrument, a vibrator of fibrous material loosely aggregated, whereby the electric impulses are transformed into sound-waves, substantially as described.

2. In a telephonic instrument, a vibrator consisting of a loosely-aggregated mass of fibrous material with its interstices in communication with the surrounding atmosphere, substantially as described.

3. In a magneto-telephone, the combination, with the magnet provided with a pole-piece and induction-coil thereon, of a vibrator consistin g of aloosely-aggregrated mass of fibrous magnetic material, substantially as described.

4. In amagneto-telephone, ahorscshoe-magnet having its extremities or poles brought into close proximity to one another without contact, and counterbored to receive the usual pole-pieces and induction-coils therein, substantially as and for the purpose described.

5. In amagneto telephone, the combination, with the pole-pieces and induction-coils there on, of the magnet counterbored to receive the said induction-coil, substantially as described.

6. In a telephone, the combination of a diaphragm or vibrating plate with a loosely-aggregated mass of fibrous material having its interstices in communication with the surrounding atmosphere and resting in contact with the said diaphragm, substantiallyas described.

7. In a telephone, a fibrous vibrator in the mouth-piece or sound-passage thereof, combined with a perforated or gauze retainingscreen to hold the said vibrator in place, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS A. WATSON.

Witnesses:

J os. P. LIVERMORE, N. E. O. WHITNEY. 

